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The small nuclear genome of the pufferfish, Fugu rubripes (order Tetraodontiformes), makes this species highly interesting for genome research. In order to establish the phylogenetic position of the Tetraodontiformes relative to other teleostean orders that might also have a reduced nuclear genome size, we have sequenced the mitochondrial (mt) genome of the pufferfish. The gene order, nucleotide composition and evolutionary rate of the mt genome of the fugu correspond to those of other teleosts. This suggests that the evolution of this genome has not been affected by the processes that led to the dramatic reduction of the size of the nuclear genome of the fugu. The phylogenetic analyses, which were based on the concatenated amino acid sequences of twelve protein-coding mt genes, placed the fugu among the percomorphs. The affinities between the Tetraodontiformes and either the Perciformes or the Zeiformes were limited, however. The common notion of a separate euteleostean clade remained unsupported. The analyses did not support the traditional systematic understanding that the Clupeiformes constitute a basal teleostean lineage. In addition the findings strongly suggest that three teleostean orders, the Perciformes, Zeiformes and Scorpaeniformes, are paraphyletic. [Copyright &y& Elsevier]

Inducibility of the mouse gene imap38 in the spleen has been recently described to correlate with resistance to Plasmodium chabaudi malaria. Here, we characterize the human ortholog gene himap1. The HIMAP1 34 kDa protein is localizable at the endoplasmic reticulum in transfected cells. It contains a GTP-binding domain, but it does not bind GTP, in contrast to mouse IMAP38. The himap1 gene belongs to a gene family clustered on chromosome 7q32–36 within a region highly syntenic to the mouse imap38 locus on chromosome 6B. The himap genes 1, 2, 3, and 4 display a conserved intron/exon structure. The mRNA of the himap1 gene is predominantly expressed in the spleen, in lymph nodes to a lesser extent, and only at very low levels in diverse cancer cell lines. In accordance, imap-like genes in mice and plants are associated with proliferative and apoptotic events suggesting a role in the control of cell death/survival. [Copyright &y& Elsevier]